A spectrum is an extremely expensive resource in wireless communications. Modern communications systems such as a Global System for Mobile Communications (GSM) system, a Wideband Code Division Multiple Access (WCDMA) system, and a Long Term Evolution (LTE) system usually work on a carrier lower than 3 gigahertz (GHz). As a smart terminal especially a video service appears, a current spectrum resource cannot meet explosive-growing user requirements for a capacity. A high frequency band (especially a millimeter-wave band) that has higher available bandwidth gradually becomes a candidate band for a next-generation communications system. For example, in a range of 3 GHz to 200 GHz, potential available bandwidth is approximately 250 GHz.
In the modern communications system, a multiple-antenna technology is usually used to increase a capacity and coverage of the system, or improve user experience. Another advantage of using the high frequency band is that a size in a multiple-antenna configuration can be greatly reduced, so as to facilitate site obtaining and deployment of more antennas. However, being different from an operating band in a current LTE system, the high frequency band results in a larger path loss. Particularly, factors such as atmosphere and vegetation further increase a wireless propagation loss. In this case, reliability of sending a synchronization channel, a control channel, a broadcast message, and the like in the current LTE system is affected. To resolve a coverage problem in the high frequency carrier scenario particularly the millimeter-wave scenario, an implementation method is as follows: Data is transmitted after virtual weighting is performed on multiple antenna elements in an analog domain to obtain one antenna port, so that a beamforming (BF) array gain can be obtained for data to be transmitted at each port. Therefore, a path loss in a high frequency scenario is overcome. However, because a beam formed in an array for a to-be-transmitted signal is relatively narrow, only some users in a cell can be covered. Further, analog domain-based BF and corresponding data transmission are performed in a time division manner, so as to ensure coverage for all users in the entire cell.
In the analog domain-based BF, one radio frequency (RF) chain is corresponding to virtual weighting of a group of multiple antenna elements (that is, corresponding to one analog beam), and different virtual weighting is corresponding to different RF chains. When different virtual weighting is used at different transmission moments, a switchover from one analog beam to another analog beam needs to be performed. Therefore, a switching time period for analog beam switching needs to be considered in a system frame structure design. In the prior art, a manner of configuring a switching time period for analog beam switching exists in orthogonal frequency division multiplexing (OFDM): A normal cyclic prefix (CP) in each to-be-sent modulation symbol is replaced with an empty CP, a time period of the empty CP is used as the switching time period, and a base station completes a switchover from one analog beam to another analog beam in the time period of the empty CP. Therefore, an extra guard time does not need to be reserved any longer. However, in the prior art, a switching time period is configured in each modulation symbol in a radio frame. In addition, for data carried in a to-be-sent modulation symbol, there is no need to perform analog beam switching quite frequently. Configuring an overlarge quantity of switching time periods causes great resource waste.